For the last century, the general trend in agriculture has been the consolidation of farmland into larger and larger farming operations. In 1900 the average farm size in the U.S. was about 140 acres. Today the average size is over 400. Because of the way in which farmlands were originally surveyed and parceled and the way in which land is acquired, large farms generally do not consist of contiguous plots of land. As a result, in order to manage a farm, farm equipment frequently must be moved from one site to another using public roadways.
For some self-propelled equipment this presents little problem. However, other types of farm equipment, for example combines with harvesting headers, cannot simply be driven down the road as the header portion is generally too wide to be accommodated by public roadways. Headers can be as much as 40 feet in width (about 12 m). The standard lane width in North America is about 12 feet (3.7 m). Thus, transporting a harvesting header while installed on the combine can be virtually impossible, as it would completely tie up traffic in both directions on most single lane roads, the routes typically available from field to field.
As a result, the header on a combine generally has to be removed from the combine, loaded onto a trailer lengthwise so that it can be safely transported to the next field where combining operations are to take place. A variety of solutions have generally taken the approach of removing the header and placing the header lengthwise on a trailer, the header and trailer being narrow enough to fit safely within a single lane of a roadway.
For example, U.S. Pat. No. 5,333,904 (Kuhns) discloses a trailer with supporting brackets onto which a harvesting header can be loaded and secured. The header is placed such that it is aligned longitudinally with the trailer, thereby allowing the header to be safely transported on public roadways. However, this system cannot conveniently be manipulated by a single operator since the header is placed onto the trailer. For example, a single operator may not be able to see under the header to align the header with the trailer and may need to use an additional person as a spotter. This type of loading may require skill and may not be easy to accomplish. Further, the system described in Kuhns is not readily adaptable to a variety of harvesting header configurations since brackets are used as support members. For example, combine headers which are of the flex type may not have a consistent structure on the bottom side of the frame which may make it difficult to load such headers onto a generic bracket and so specialty brackets may be required, with the type of required bracket unique between headers.
Later approaches to the problem include those such as are disclosed in U.S. Pat. No. 6,047,989 (Wood). Wood describes adjustable header support units that are configured to be more readily adapted to various header units. Wood, however, describes simply adding a plurality of mounting points for the supporting brackets, such that the user can select a particular bracket mount point to more or less align with the desired engagement point on the header. Given its size, the system described in Wood is still not particularly amenable to use by a single operator and still retains defined attachment points, which may or may not perfectly align with sites on the header to which one might wish to secure the header to the trailer.
Others have described trailers that allow the header to be rotated around the longitudinal axis in order to save space and make it easier to effect repairs. For example, U.S. Pat. No. 6,428,047 (Kaderabek) discloses a trailer that allows the header to be placed on the trailer and then pivotally rotated in order to either provide access to the underside of the header, or to save space for storage of the header in the off-season. A variation of this same theme is disclosed in U.S. Patent Publication No. 2009/0189382 (Nubel et al.). Still others have disclosed a trailer with a steerable wheel system on which headers can be transported, as is disclosed in U.S. Patent Publication No. 2010/0052289 (Frey et al.).
The above described devices suffer from limitations. For example, by using a fixed size trailer, a system may not be easily adapted for headers of difference sizes. Some of the above described systems are effectively large trailers that are difficult for a single operator to manipulate. Using the equipment described above may require two or three people in order to situate the trailer and move the header from the combine to the trailer.